1. Field of the Invention
The present invention relates to a method, system and program for improving print quality enhancement and, in particular, generating a look-up table that enhances print quality.
2. Description of the Related Art
To print an image, a print engine processor, referred to herein as a raster image processor, converts the image in a page description language or vector graphics format to a bit mapped image indicating a value to print at each pixel of the image. Each bit representing a pixel that is “on” is converted to an electronic pulse. The electronic pulses generated from the raster pel data at which to deposit toner turns the laser beam on to positively charge the surface of a rotating drum, which is an organic photo-conducting cartridge (OPC), that has a coating capable of holding an electrostatic charge. The laser beam turns on and off to beam charges at pixel areas on a scan line across the drum that will ultimately represent the output image. After the laser beam charges all pels on the scan line indicated in the raster data, the drum rotates so the laser beam can place charges on the next scan line. The drum with the electrostatic positive charges then passes over negatively charged toner. The negatively charged toner is then attracted to the positive charged areas of the drum that form the image. The paper, which is negatively charged, passes over the roller drum and attracts the toner as the areas of the roller drum with the toner are positively charged to transfer the toner forming the image from the roller drum to the paper.
Many laser printers may filter the bit map images using a look-up table to alter the pulses generated for each pixel to accomplish a certain filtering result. For instance, filters can be used to provide an economy mode where toner is reduced, remove jagged edges, improve print quality or reduce the density of images. Typically, the laser printer will gather an area of data and replace either one or all the pulse values for the pixels based on the gathered area of pixel data matching a value in the look-up table. Print quality enhancement look-up tables adjust input pels based on the values in surrounding pels to provide anti-aliasing, boldness control, and remove jagged edges.
Notwithstanding current print quality enhancement algorithms for generating values in a look-up table, there is a need for an improved methodology for generating look-up tables to adjust input pel values to enhance print quality.